[meteorite-list] Mars Rovers Still Going Strong After A Year of Exploring

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Tue Jan 4 11:13:33 2005
Message-ID: <200501041613.IAA20053_at_zagami.jpl.nasa.gov>

http://www.spaceflightnow.com/mars/mera/050103oneyear.html

Mars rovers still going strong after a year of exploring
BY SPACEFLIGHT NOW
January 3, 2005

The remarkably inexhaustible Mars rovers, built to explore opposite
sides of the Red Planet for three months in early 2004 and uncover proof
of past water on Earth's neighbor, are still trucking along to the
amazement and delight of scientists one year after the adventure began.

Mars Exploration Rover Spirit arrived in the vast Gusev Crater on
January 3, 2004, followed three weeks later by the twin craft
Opportunity on the expansive plains of Meridiani. The $820 million
mission was launched by NASA to scour the landscape and rocks to
determine if Mars had a watery history that could have supported life.

Opportunity quickly found evidence that standing water once covered its
landing site, answering a fundamental question about the Red Planet.
Later, Spirit successfully found water clues at its locale, too.

As the months flew past, both rovers continued to roll and their
missions were extended. The 90-day warranties were surpassed as the
vehicles racked up greater distances on their odometers. Today, Spirit
and Opportunity remain hard a work. And not even the rovers' lead
scientist, Steve Squyres of Cornell University, thought the craft would
last this long.

"No, and I had pretty wild dreams for them. I thought maybe they would
go four or five months, maybe six, and over their entire lifetime they
might drive a thousand yards, something like that," he said Monday.

"But three, four kilometers, a year of operation, climbing mountains,
no, I would never have guessed it."

To date, Spirit has driven over four kilometers as it traveled from its
landing site to the rim of Bonneville Crater and is now ascending
Husband Hill, named for the fallen commander of space shuttle Columbia.
Opportunity has rolled two kilometers and spent much of its time inside
the small Eagle Crater in which is landed and the stadium-sized
Endurance Crater. The rovers have beamed 86 gigabits of data and 62,000
pictures to Earth, said Jim Erickson, the project manager at NASA's Jet
Propulsion Laboratory.

"At the Spirit site we are climbing higher and higher in the range of
mountains we are exploring called the Columbia Hills. As we've done so,
we've found some completely different geologic materials that are
telling us something about the history of these hills that is completely
different than anything seen before," Squyres said.

"With Opportunity we have these flat plains extending off to the south
and then two miles away we have this fantastically complicated
'badlands' kind of topography. We call it the etched terrain but we
really don't know what it is. We're going to go down there and explore
the rocks there and they are going to tell us, I think, something very
new and different compared to anything we've seen so far."

While discoveries are still being made, the legacy of the Mars rovers
achieved so far is showing the planet had an environment for life.

"I think the most important single finding from the mission is Mars at
one time in one place on the surface had conditions that probably would
have been suitable for supporting life. That doesn't say life was there.
What we can say is Mars was a habitable world. Whether it was inhabited
is a totally different question. But now we know where to go and look,"
Squyres said.

"The thing that really makes me most interested now, the thing that
really gets me going when I think about what we have learned, is whether
or not the rocks -- especially where Opportunity landed -- could
preserve evidence of what might have been in that water. We've got
compelling evidence that water was there, that it was a habitable
environment, so forth and so on, but was there something living there?
The thing that is beautiful about these rocks is that they are the kind
of rocks that are very good at preserving microscopic fossils. So if we
could actually get some of these materials and get them back to Earth,
then we might be able to try and answer that question."

But such a sample return mission won't happen before the next decade.
NASA plans to launch a sophisticated orbiter to snap highly detailed
pictures of the Martian surface in August, a lander with a digging arm
to probe water ice near the north pole in 2007 and a nuclear-powered
science rover in 2009.

The continuing studies by Spirit and Opportunity are aimed at gathering
more detail on what the environment was like on Mars.

"We're recently getting clues that it was actually a pretty arid
environment. It was dry much of the time and then there would be these
occasional inundations of water. So it was an alternating wet and dry
kind of climate. We've also been getting increasing clues that the water
may have been very acidic; it may have been sort of sulfuric acid as
opposed to nice, clear drinking water. So we're getting more and more
detail on what the environment was like with each passing month,"
Squyres said.

Life can be found in highly acidic water on Earth today, he said.

"So these kinds of environments are certainly capable of supporting
life. Whether life could first take hold in a place like that is
something that we really don't know."

Scientists are trying to use every day to the fullest, not knowing when
the rovers will reach their end.

"They are in remarkably good shape. With Spirit we had a little issue
with the right front wheel for a while where it was taking more
electrical current to turn it than it used to. We think that was because
of a problem with the lubricants, the grease in the gear box. But with
time and by applying a little bit of heat we've actually been able to
spread that grease around a little bit and that wheel has actually
gotten better. So right now these two vehicles are dirty, they're
scratched up, but they are still going and are in very good shape,"
Squyres said.

Both rovers weathered the worst of wintertime and reduced solar power,
but now spring is approaching.

"We survived the winter. That is the key thing -- we survived the
winter. The sun is coming back towards us; the power is going up. The
thing we have to worry about though, we've got weather to worry about.
What's happening is we're starting to see little dust storms. Not big
ones, not big global ones, not something that threatens the lives of the
rovers, but we've begun to see recently in the last week or two evidence
of little local storms. So we're actually tracking weather systems on
Mars to keep track of how it's going to affect the vehicles."

Rover project manager Erickson says the level dust accumulation on the
vehicles' power-generating solar arrays is less than engineers expected
and the frigid temperatures that take their toll on the craft have been
less severe than predicted.

"The rovers have been lucky so far. The power situation, which is rosy,
wasn't what we expected. The solar panels turned out to be staying much
cleaner than we planned on. And the overnight temperature lows that
we've been seeing are much less than we planned for. We were ready to
accept much colder temperatures. But it's all to the good, it means
we're able to continue on and we're in a strong position to continue
exploration with both of the rovers. Bad things could happen to us at
any time. Random part failures could lose the missions tomorrow. But as
long as we have them, we're going to keep using them to the best of
their ability."

The project's primary mission was financed to last three months. But
NASA has extended the mission and both rovers are funded through this
March.

"It costs about $3 million a month to keep the rovers going. It seems
inconceivable to me that if the missions are still producing good
science that we will not find a way to keep them going. We will manage
somehow," said Firouz Naderi, manager of NASA's Mars Exploration Program
at JPL.

Engineers acknowledge there are countless scenarios that would stop the
craft dead in their tracks. No one knows if either rover will survive
another couple of months.

"It depends on what kills them," Squyres said.

"One of the things that could do it is dust buildup on the solar arrays.
The solar arrays...are pretty clean right now, especially on
Opportunity. So if it is that, they could last for many months longer.
But there are other things that could do it too. We have a lot of moving
parts on these vehicles -- there's lots of motors, lots of gear boxes,
lots of things that can wear out. If that starts to happen, then it will
be an issue. The other possibility is the electronics. There are a lot
of electrical parts in these things that if they fail -- bam! -- that's
it, the rover wouldn't wake up the next morning.

"So we try to plan for many months of operations but on each individual
day we try to drive them literally like there's no tomorrow."

Squyres said Monday that Spirit and Opportunity have provided the
"adventure of a lifetime" and proved a prediction he made last January
after the landings that scientists were about to embark on "the coolest
geology field trip in human history."

"The thing about exploration is you never know what is over that next
hill, you never know what is going to come next. These rovers still have
a lot of capability left in them. We are pushing them very hard, we're
pushing ourselves very hard and we'll see what Mars has to show us."

But the reality is the rovers won't last forever.

"It is going to be a hard day. You grow very attached to them. They've
developed their own personalities, they are pieces of machinery that we
really care about and when we lose them it is going to be a rough day.
But they will have died honorable deaths, when it does happen. They have
achieved far more than any of us expected. It will be sad but in its own
way satisfying," Squyres said.
Received on Tue 04 Jan 2005 11:13:23 AM PST